2 Measurement Is a determination of the amount of something Is defined as a comparison to a known standardWhat does “5 feet tall” mean????Do you have to know what a foot is in order for this to make sense?Measurements have two parts, a number value and a unit
3 Units and Standards What is a standard ? 1.) Historically things such as hands and feet were used to make measurements, and other things were compared to that size.2.) A standard is something that you compare other amounts to.
4 Two Measurement Systems English system-used for everyday measurement in the US.Include units of miles, feet, inches, pounds, pints, quarts, gallons, cups, and teaspoonsMetric System
5 MeasurementIn 1960 an International Committee agreed to a system of standards to be used by scientists worldwide.Scientists use the metric system or SI for le System Internationale d’UnitsMakes sharing data easierGoal for using metric system was to have all units of measurement be related
6 Metric System Units include a Base unit and prefix Base units include Liters, meters, and gramsPrefixes multiply or divide the base units by multiples 10
7 Prefixes Prefix Symbol Meaning As a number kilo- k thousand 1,000 mega-Mmillion1,000,000giga-Gbillion1,000,000,000deci-dtenth0.1centi-chundredth0.01milli-mthousandth0.001micro-mmillionth
8 Conversion factors…. 1000 milli-units = 1 base unit 100 centi-units = 1 base unit10 deci- units = 1 base unit1000 base units = 1 kilo-unit
9 1. 2 Time and Distance Time is used in two ways To indicate a particular moment in the past or the futureTomorrow at 3:00To indicate a quantity of time….30 seconds minutes, 15 seconds
10 Measuring Length/Distance Use a ruler/taper measureLine up from zero not the end of the rulerSmall divisions are millimeters
12 MassWeight is the force of gravity acting on an object, mass is the amount of matter in an object. (they are different things)Metric unit of mass is the gram1gram is defined as the mass of 1 cm3 of water at 4 ºC.1 kg = 1 L of water1 kg = 2.2 lbs1 g = 1 small paper clip1 mg = 10 grains of salt or 2 drops of water.
13 Measuring Mass Use a triple beam balance First balance it at zero. Then put item onThen move one weight at a timeWhen balanced, add up the weights
14 Volume Defined as the space occupied by some object or substance Liter a common unit, cubic meter (m3) is SI unit 1 L about 1/4 of a gallon - a quart1 mL is about 20 drops of water or 1 sugar cube1 ml = 1 cm3
15 Measuring Volume of a Liquid Use a graduated cylinder.The water will curve in the cylinder.Hold it level with your eye.Read the bottom of the curve (meniscus)Measures in milliliters mL.
16 Measuring Volume of a solid Object Can be accomplished by using the “displacement method”Objects in water will displace, or push aside, their volume in water.1. Record initial volume2. Record Final Volume3. Subtract initial volume from final volume to get volume of object
17 Measuring Volume of Regular Solid Object You can calculate the volume of a regular object such as a cube or rectangular solid by using the equationVolume = Length X Width X HeightVolume calculator
18 Density Density = Mass Volume Description of matter that is a comparison of mass and volumeCalculated using the equationDensity = MassVolumeDensity of water = 1 g/cm3 = 1000kg/m3If material density > water, it will sinkIf material density < water, it will float
19 Temperature Measured with a thermometer Common metric units are either Celsius or KelvinMeasure of the average kinetic energy of molecules or atoms of a substance (faster ones have more KE and are “hotter”)Water freezes at 0°C, boils at 100°C
21 TimeCommon base unit of seconds, but can be measured in hours/days/years/etc..1 year = 365 days1 day = 24 hours1 hour = 60 minutes1 minute = 60 seconds
22 ForceUse a force gauge to measure, or a spring scale like we use in this classMeasure in units of “Newtons”
23 Metric conversions Changing the unit Does not change the size of the measurementIf the unit gets bigger the number gets smallerIf the unit gets smaller the number gets biggerMath with multiples of 10We will cancel out units to make sure we set the problem up right
24 Metric conversions“A common race is the 5 K, which is 5 km. How many meters is this?”Given unit -kmUnit wanted –mThe unit gets smaller, so the number must get bigger1000 m = 1 km
25 Metric conversions 1000 m Distance in m = 5 km x 1 km Distance in m = 5000 m
26 Metric conversionsThe recommended daily requirement of vitamin C is 500 mg. How many grams is this?1 gmass in g = 500 mgx1000 mgmass in g = 0.5 g